CVE-2024-30103Public exploitNetwork attack vector

Authenticated code execution via crafted Outlook form

Published Jun 11, 2024 · Updated Aug 10, 2026

Remote code execution in Microsoft Outlook allows remote authenticated users to run code by sending a malicious Outlook form. Outlook's form-instantiation path compares registry paths against a denylist without canonicalizing backslash variants, then lets RegCreateKeyExA expand the crafted path and load an attacker-supplied DLL. Exploitation requires valid Exchange credentials, but the message can trigger in Outlook without further user interaction and code runs in the Outlook process.

CVSS severity8.8
High
EPSS probability3.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Remote code execution in Microsoft Outlook allows remote authenticated users to run code by sending a malicious Outlook form. Outlook's form-instantiation path compares registry paths against a denylist without canonicalizing backslash variants, then lets RegCreateKeyExA expand the crafted path and load an attacker-supplied DLL. Exploitation requires valid Exchange credentials, but the message can trigger in Outlook without further user interaction and code runs in the Outlook process.

The record

CVE
CVE-2024-30103
Published
Jun 11, 2024
Updated
Aug 10, 2026
Vendor
Microsoft
Product
Microsoft Office 2019
Classifications
CWE-184, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 11, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=19.0.0 <https://aka.ms/OfficeSecurityReleases

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Microsoft · Microsoft Office 2019version=19.0.0 <https://aka.ms/OfficeSecurityReleases
Microsoft · Microsoft Outlook 2016version=16.0.0.0 <16.0.5452.1000
Microsoft · Microsoft Office LTSC 2021version=16.0.1 <https://aka.ms/OfficeSecurityReleases
Microsoft · Microsoft 365 Apps for enterpriseversion=16.0.1 <https://aka.ms/OfficeSecurityReleases

Published CVSS scores

8.8Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-184Incomplete List of Disallowed Inputs
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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